aoqi@0: /*
aoqi@0:  * Copyright (c) 2010, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_PROMOTIONINFO_HPP
aoqi@0: #define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_PROMOTIONINFO_HPP
aoqi@0: 
aoqi@0: #include "gc_implementation/concurrentMarkSweep/freeChunk.hpp"
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: 
aoqi@0: // Forward declarations
aoqi@0: class CompactibleFreeListSpace;
aoqi@0: 
aoqi@0: class PromotedObject VALUE_OBJ_CLASS_SPEC {
aoqi@0:  private:
aoqi@0:   enum {
aoqi@0:     promoted_mask  = right_n_bits(2),   // i.e. 0x3
aoqi@0:     displaced_mark = nth_bit(2),        // i.e. 0x4
aoqi@0:     next_mask      = ~(right_n_bits(3)) // i.e. ~(0x7)
aoqi@0:   };
aoqi@0: 
aoqi@0:   // Below, we want _narrow_next in the "higher" 32 bit slot,
aoqi@0:   // whose position will depend on endian-ness of the platform.
aoqi@0:   // This is so that there is no interference with the
aoqi@0:   // cms_free_bit occupying bit position 7 (lsb == 0)
aoqi@0:   // when we are using compressed oops; see FreeChunk::is_free().
aoqi@0:   // We cannot move the cms_free_bit down because currently
aoqi@0:   // biased locking code assumes that age bits are contiguous
aoqi@0:   // with the lock bits. Even if that assumption were relaxed,
aoqi@0:   // the least position we could move this bit to would be
aoqi@0:   // to bit position 3, which would require 16 byte alignment.
aoqi@0:   typedef struct {
aoqi@0: #ifdef VM_LITTLE_ENDIAN
aoqi@0:     LP64_ONLY(narrowOop _pad;)
aoqi@0:               narrowOop _narrow_next;
aoqi@0: #else
aoqi@0:               narrowOop _narrow_next;
aoqi@0:     LP64_ONLY(narrowOop _pad;)
aoqi@0: #endif
aoqi@0:   } Data;
aoqi@0: 
aoqi@0:   union {
aoqi@0:     intptr_t _next;
aoqi@0:     Data     _data;
aoqi@0:   };
aoqi@0:  public:
aoqi@0:   inline PromotedObject* next() const {
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:     PromotedObject* res;
aoqi@0:     if (UseCompressedOops) {
aoqi@0:       // The next pointer is a compressed oop stored in the top 32 bits
aoqi@0:       res = (PromotedObject*)oopDesc::decode_heap_oop(_data._narrow_next);
aoqi@0:     } else {
aoqi@0:       res = (PromotedObject*)(_next & next_mask);
aoqi@0:     }
aoqi@0:     assert(oop(res)->is_oop_or_null(true /* ignore mark word */), "Not an oop?");
aoqi@0:     return res;
aoqi@0:   }
aoqi@0:   inline void setNext(PromotedObject* x) {
aoqi@0:     assert(((intptr_t)x & ~next_mask) == 0, "Conflict in bit usage, "
aoqi@0:            "or insufficient alignment of objects");
aoqi@0:     if (UseCompressedOops) {
aoqi@0:       assert(_data._narrow_next == 0, "Overwrite?");
aoqi@0:       _data._narrow_next = oopDesc::encode_heap_oop(oop(x));
aoqi@0:     } else {
aoqi@0:       _next |= (intptr_t)x;
aoqi@0:     }
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:   }
aoqi@0:   inline void setPromotedMark() {
aoqi@0:     _next |= promoted_mask;
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:   }
aoqi@0:   inline bool hasPromotedMark() const {
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:     return (_next & promoted_mask) == promoted_mask;
aoqi@0:   }
aoqi@0:   inline void setDisplacedMark() {
aoqi@0:     _next |= displaced_mark;
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:   }
aoqi@0:   inline bool hasDisplacedMark() const {
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:     return (_next & displaced_mark) != 0;
aoqi@0:   }
aoqi@0:   inline void clear_next()        {
aoqi@0:     _next = 0;
aoqi@0:     assert(!((FreeChunk*)this)->is_free(), "Error");
aoqi@0:   }
aoqi@0:   debug_only(void *next_addr() { return (void *) &_next; })
aoqi@0: };
aoqi@0: 
aoqi@0: class SpoolBlock: public FreeChunk {
aoqi@0:   friend class PromotionInfo;
aoqi@0:  protected:
aoqi@0:   SpoolBlock*  nextSpoolBlock;
aoqi@0:   size_t       bufferSize;        // number of usable words in this block
aoqi@0:   markOop*     displacedHdr;      // the displaced headers start here
aoqi@0: 
aoqi@0:   // Note about bufferSize: it denotes the number of entries available plus 1;
aoqi@0:   // legal indices range from 1 through BufferSize - 1.  See the verification
aoqi@0:   // code verify() that counts the number of displaced headers spooled.
aoqi@0:   size_t computeBufferSize() {
aoqi@0:     return (size() * sizeof(HeapWord) - sizeof(*this)) / sizeof(markOop);
aoqi@0:   }
aoqi@0: 
aoqi@0:  public:
aoqi@0:   void init() {
aoqi@0:     bufferSize = computeBufferSize();
aoqi@0:     displacedHdr = (markOop*)&displacedHdr;
aoqi@0:     nextSpoolBlock = NULL;
aoqi@0:   }
aoqi@0: 
aoqi@0:   void print_on(outputStream* st) const;
aoqi@0:   void print() const { print_on(gclog_or_tty); }
aoqi@0: };
aoqi@0: 
aoqi@0: class PromotionInfo VALUE_OBJ_CLASS_SPEC {
aoqi@0:   bool            _tracking;      // set if tracking
aoqi@0:   CompactibleFreeListSpace* _space; // the space to which this belongs
aoqi@0:   PromotedObject* _promoHead;     // head of list of promoted objects
aoqi@0:   PromotedObject* _promoTail;     // tail of list of promoted objects
aoqi@0:   SpoolBlock*     _spoolHead;     // first spooling block
aoqi@0:   SpoolBlock*     _spoolTail;     // last  non-full spooling block or null
aoqi@0:   SpoolBlock*     _splice_point;  // when _spoolTail is null, holds list tail
aoqi@0:   SpoolBlock*     _spareSpool;    // free spool buffer
aoqi@0:   size_t          _firstIndex;    // first active index in
aoqi@0:                                   // first spooling block (_spoolHead)
aoqi@0:   size_t          _nextIndex;     // last active index + 1 in last
aoqi@0:                                   // spooling block (_spoolTail)
aoqi@0:  private:
aoqi@0:   // ensure that spooling space exists; return true if there is spooling space
aoqi@0:   bool ensure_spooling_space_work();
aoqi@0: 
aoqi@0:  public:
aoqi@0:   PromotionInfo() :
aoqi@0:     _tracking(0), _space(NULL),
aoqi@0:     _promoHead(NULL), _promoTail(NULL),
aoqi@0:     _spoolHead(NULL), _spoolTail(NULL),
aoqi@0:     _spareSpool(NULL), _firstIndex(1),
aoqi@0:     _nextIndex(1) {}
aoqi@0: 
aoqi@0:   bool noPromotions() const {
aoqi@0:     assert(_promoHead != NULL || _promoTail == NULL, "list inconsistency");
aoqi@0:     return _promoHead == NULL;
aoqi@0:   }
aoqi@0:   void startTrackingPromotions();
aoqi@0:   void stopTrackingPromotions(uint worker_id = 0);
aoqi@0:   bool tracking() const          { return _tracking;  }
aoqi@0:   void track(PromotedObject* trackOop);      // keep track of a promoted oop
aoqi@0:   // The following variant must be used when trackOop is not fully
aoqi@0:   // initialized and has a NULL klass:
aoqi@0:   void track(PromotedObject* trackOop, Klass* klassOfOop); // keep track of a promoted oop
aoqi@0:   void setSpace(CompactibleFreeListSpace* sp) { _space = sp; }
aoqi@0:   CompactibleFreeListSpace* space() const     { return _space; }
aoqi@0:   markOop nextDisplacedHeader(); // get next header & forward spool pointer
aoqi@0:   void    saveDisplacedHeader(markOop hdr);
aoqi@0:                                  // save header and forward spool
aoqi@0: 
aoqi@0:   inline size_t refillSize() const;
aoqi@0: 
aoqi@0:   SpoolBlock* getSpoolBlock();   // return a free spooling block
aoqi@0:   inline bool has_spooling_space() {
aoqi@0:     return _spoolTail != NULL && _spoolTail->bufferSize > _nextIndex;
aoqi@0:   }
aoqi@0:   // ensure that spooling space exists
aoqi@0:   bool ensure_spooling_space() {
aoqi@0:     return has_spooling_space() || ensure_spooling_space_work();
aoqi@0:   }
aoqi@0:   #define PROMOTED_OOPS_ITERATE_DECL(OopClosureType, nv_suffix)  \
aoqi@0:     void promoted_oops_iterate##nv_suffix(OopClosureType* cl);
aoqi@0:   ALL_SINCE_SAVE_MARKS_CLOSURES(PROMOTED_OOPS_ITERATE_DECL)
aoqi@0:   #undef PROMOTED_OOPS_ITERATE_DECL
aoqi@0:   void promoted_oops_iterate(OopsInGenClosure* cl) {
aoqi@0:     promoted_oops_iterate_v(cl);
aoqi@0:   }
aoqi@0:   void verify()  const;
aoqi@0:   void reset() {
aoqi@0:     _promoHead = NULL;
aoqi@0:     _promoTail = NULL;
aoqi@0:     _spoolHead = NULL;
aoqi@0:     _spoolTail = NULL;
aoqi@0:     _spareSpool = NULL;
aoqi@0:     _firstIndex = 0;
aoqi@0:     _nextIndex = 0;
aoqi@0: 
aoqi@0:   }
aoqi@0: 
aoqi@0:   void print_on(outputStream* st) const;
aoqi@0:   void print_statistics(uint worker_id) const;
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: #endif // SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_PROMOTIONINFO_HPP